                                                 Customer
                            ------------------   Service  ----------
                           |                  |  Model   |          |
PETRA as                   |     Service      |<-------->| Customer |
Customer Service           |   Orchestrator   |    (a)   |          |
related API                |                  |           ----------
                            ------------------
                               .          .
##########################    .            .        (b)   -----------
                             . (b)          .      ......|Application|
                            .                .     :     |  BSS/OSS  |
PETRA as                   .                  .    :      -----------
Service related API       .  Service Delivery  .   :
                         .       Model          .  :
                 ------------------    ------------------
                |                  |  |                  |
#############   |     Network      |  |     Network      |
                |   Orchestrator   |  |   Orchestrator   |
                |                  |  |                  |
                .------------------    ------------------.
PETRA as               .         :                       :        .
Network API   .         : Network Configuration :         .
            .            :        Model          :         .
      ------------     ------------     ------------    ------------
     |            |   |            |   |            |  |            |
###  | Controller |   | Controller |   | Controller |  | Controller |
     |            |   |            |   |            |  |            |
      ------------     ------------     ------------    ------------
         :              .       .                 :            :
         :             .         .      Device    :            :
         :            .           . Configuration :            :
         :            .           .     Model     :            :
     ---------     ---------   ---------     ---------      ---------
    | Network |   | Network | | Network |   | Network |    | Network |
    | Element |   | Element | | Element |   | Element |    | Element |
     ---------     ---------   ---------     ---------      ---------
